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Interesting, thanks for the info. I was always somewhat concerned about the abundance of critical raw materials for ARC or other fusion projects. I had assume

Interesting, thanks for the info. I was always somewhat concerned about the abundance of critical raw materials for ARC or other fusion projects. I had assumed that the rare-earth elements in the REBCO tape, e.g. yttrium, would be constrained. I didn't suspect that beryllium could be a limiting resource. But I wonder if the lack of supply is related to true scarcity or just to a lack of a profitable market currently. These are all questions I'd want to ask domain experts in mining and fusion. But I agree that fission would be a better solution for baseload, at least for the next 10-20 years. If only newer modular designs were actually approved...

pfdietz 5y ago
The ARC design (see https://arxiv.org/abs/1409.3540 https://arxiv.org/abs/1409.3540 for details) uses surprisingly little yttrium. The superconductor is only about 1% of the tapes, and the tapes are only a faction of the coils, and the coils mass is just a fraction of the mass of the coil support structure. I think the total amount of yttrium will be in the tens of kilograms, if that. I have a suspicion that this is being funded at all because the magnet technology would be useful in non-fusion contexts (hybrid electric aircraft, superconducting generators in wind turbines.) In contrast, IIRC a single ARC reactor of that design would have 90 tonnes of beryllium (although that could be reduced by half if the secondary loop used a different molten salt.)